Why do groups of loons congregate on the lake?

SOCIAL SPECTACLE – In summer, large groups of loons from neighboring lakes get together for social interaction. Scientists have suggested various motivations for these congregations.

Photo by Brian M. Collins

QAt our cabin in northern Minnesota, we normally have only one pair of loons that nest on the lake. However, early on most summer mornings in 2011, we noticed eight to 10 loons gathering together on the lake for an hour or so, diving and swimming. We call it “The Loon Breakfast Club.” After the morning breakfast stop, they fly off. Is this behavior unusual? Are they gathering to socialize?

– Barb, Minn.

A In summer, many loons begin each morning by flying to a rendezvous lake to participate in some social bonding, like you have observed. For those who haven’t witnessed it, a loon social gathering is an impressive event. As loons arrive, first flying past for a quick assessment and then gliding in silently, fellow sharp-eyed birds on the water greet them with an excited “hoot,” a salutation given nearly an octave higher than the usual contact call. With toes dangling and body held upright, each loon comes in on a high-speed landing that starts with the tips of their feet dragging in the water and ends in a chest-first splashdown. Coming to rest, each loon begins to seek out others, and they all begin to congregate into a loose raft of loons. In the skies above, other loons call in a hurried tremolo, signaling their intent to land and join the group, which settles into a routine that looks much like a dance. The whole raft then swims about in a sort of slowly turning “square dance,” bills turned downward, red eyes looking in toward the middle of the circle. When one loon dives, the rest swim nervously, plunging faces underwater to track the diver’s progress. With poetry, grace and perhaps a dose of mistrust, the swimming circle erupts suddenly with loons splashing, chasing, dipping, diving and calling wildly. The rogue loon suddenly erupts on the waves, pursuing the tail of another, and the two chase each other. Sometimes they pursue one another tirelessly over the water, wings churning froth in a competitive breaststroke until one bird is driven away from the group. Other times, the loons diffuse tension with an assortment of intense behaviors on splayed wings, rising powerfully from the water and calling. Scientists have suggested a number of hypotheses for these social gatherings, including the possibility that the loons are preparing for fall migration. However, the apparent reasons for loon groups are often inconsistent. Maybe the “square dance” behavior represents a sort of aquatic chicken coop, a tussle for pecking order. Perhaps it involves a bit of play and learning, important skill-building behavior in the animal kingdom. It is even possible that the birds are already working on settling next year’s mating-season issues.

GETTING NOTICED – Loon congregations are quite common on many lakes. At these social gatherings, the loons participate in a sort of energetic “square dance” with each other.

I have always assumed these summer social events were for loons that
had suffered some sort of tragedy in their nesting cycle, since these
gatherings occur when many other loons are still paired, territorial and
rearing chicks of all ages. Years of observations seemed to validate my
theory, until one summer day in 2009. I was paddling on a very small lake, a respectable distance from the only breeding pair of loons. Their chick, a healthy, downy fuzz ball, spent much of its time swimming with its parents, rousing and flapping its tiny, unfeathered wings and taking tiny aquatic offerings from gentle bills. Peace, comfort, and tranquility were a virtual guarantee for the loon family. Suddenly, with a flurry of wings, I became witness to a breeding pair of loons participating in one of these social gatherings. The mated pair started the morning in solitude, alone with their chick. By the time the sun had risen just above the trees, they “parked” their precious loon chick in a weedy bay, departed the lake, and seemed to round up loons from adjacent lakes with flight tremolo calls. Soon, the air was filled with calling loons in all directions. Splashing down in various parts of the small lake, the adults began swimming toward each other until they had made their circle. The square dance continued for some time, the mated male occasionally driving others off with aggressive splashing and chasing. Within an hour, only the pair remained, and they quickly reunited with their chick and had the lake to themselves once again. Each and every time I witness one of these morning social gatherings, I feel more honored to observe the event, and I learn something new. Paradoxically, the more information I gain through observation, the less I feel that I know what is really going on. One thing is certain: Loons thrive on social contact with other loons.

Brian Collins enjoys photographing loons from a respectful distance. On several occasions, though, rafts of socializing loons have actually followed his canoe! To view more of Brian’s wildlife photography, visit www.imagesinnaturallight.com.